 /*******************************************************************************
  * Copyright (c) 2000, 2006 IBM Corporation and others.
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  * IBM Corporation - initial API and implementation
  *******************************************************************************/
 package org.eclipse.ui.operations;

 import org.eclipse.core.commands.operations.IUndoContext;
 import org.eclipse.ui.IActionBars;
 import org.eclipse.ui.IWorkbenchPartSite;
 import org.eclipse.ui.actions.ActionFactory;
 import org.eclipse.ui.actions.ActionGroup;

 /**
  * <p>
  * UndoRedoActionGroup provides standard undo and redo action handlers for a
  * workbench part site. It supports filtering of undo or redo on a particular
  * undo context. The undo context can be optionally pruned, which means the
  * context will be flushed actively whenever an invalid operation is found on
  * top of its history. This class may be instantiated by clients.
  * </p>
  *
  * @since 3.1
  */
 public final class UndoRedoActionGroup extends ActionGroup {

     private UndoActionHandler undoActionHandler;

     private RedoActionHandler redoActionHandler;

     /**
      * Construct an undo redo action group for the specified workbench part
      * site, using the specified undo context.
      *
      * @param site
      * the workbench part site that is creating the action group
      * @param undoContext
      * the undo context to be used for filtering the operation
      * history
      * @param pruneHistory
      * a boolean that indicates whether the history for the specified
      * context should be pruned whenever an invalid operation is
      * encountered.
      */
     public UndoRedoActionGroup(IWorkbenchPartSite site,
             IUndoContext undoContext, boolean pruneHistory) {

         // create the undo action handler
 undoActionHandler = new UndoActionHandler(site, undoContext);
         undoActionHandler.setPruneHistory(pruneHistory);

         // create the redo action handler
 redoActionHandler = new RedoActionHandler(site, undoContext);
         redoActionHandler.setPruneHistory(pruneHistory);
     }

     /*
      * (non-Javadoc)
      *
      * @see org.eclipse.ui.actions.ActionGroup#fillActionBars(org.eclipse.ui.IActionBars)
      */
     public void fillActionBars(IActionBars actionBars) {
         super.fillActionBars(actionBars);
         if (undoActionHandler != null) {
             actionBars.setGlobalActionHandler(ActionFactory.UNDO.getId(),
                     undoActionHandler);
             actionBars.setGlobalActionHandler(ActionFactory.REDO.getId(),
                     redoActionHandler);
         }
     }
 }

